Classic Cryptography

Introduction

Many of us enjoyed watching or reading detective-based stories because of the mysteries that hid within. For most of the time, each and every line of a character might be a hint to solve some mysteries. As inspired by the classic story of “Indiana Jones” and transferred to other similar yet twisted movies, deciphering the hidden messages plays a significant role. The codes were created by the person who wants to preserve something or hide from the other people. In a very obvious sense, the codes are created with only few people who can understand it and the job of the decoder or decipher is to analyze or interpret the messages embedded in the materials he or his group encountered. Moreover, drunk by too much watching movies, most of the messages are locked in to stones or relic rocks that are vulnerable and easily to destroy. But in reality, the codes are not merely invented messages just to play with the viewers’ imagination, nor are the profession made just to look for an adventure.

What is Cryptography?

From the Greek word “kryptos” which means “hidden secret” and “grapho” which means “I write”, cryptography is made as a practice and study of hiding the information. In modern world, the cryptography is a discipline that the professionals use such in mathematics, computer science, and engineering. The other application of the cryptography is seen on the ATM cards, computer passwords, and other electronic equipments in order to protect the user and the information written. Cryptography is also considered as similar with encryption as the conversion of information in which an ordinary person might mistakenly judged as nonsense messages. Starting from mathematical and information theory background, cryptography can be traced. The ciphers with two major categories – substitution and transposition are analyzed with encoding, decoding algorithms, cryptanalysis matters and there some applications as well as the machines invented used in cryptography.

Classical Cryptography

Classical Cryptography, the history of which has at least 4000 years as we know, is mainly used in both diplomacy and war over centuries. However, comparing to modern cryptography which are mainly used in computer security nowadays, most of the classical ciphers are claimed to be vulnerable in front of today’s powerful computers. The founded knowledge of classic cryptography became the motivation for the inventors to create applications and technologies with security features. The cunning mind of the people who set the codes is to generate the confusion and diffusion for the people.

Back in the history of war, the messages are hidden under the codes with a purpose to avoid the enemy gain the knowledge in advancing their team. Typically, the sender retained the ability to decrypt the information and therefore avoid unwanted persons being able to read it. Since WWI and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application more widespread. Alongside the advancement in cryptology-related technology, the practice has raised a number of legal issues, some of which remain unresolved.

The Purpose of Cryptography

Even in ancient times, the cryptography is already used by the people or historians to be part of their writing. Since there is no suggested writing style, the Egyptians used to document their history through the use of art of hieroglyphs. It maybe some form of art but in a deep sense, it reveals messages regarding the adventures of their Pharaohs, their legends, and even their traditions. However, this standard of writing revived through the existence of the World Wars I & II. The secret message writing once again invented to provide a comprehensive yet short battle plans. The main aim of this is to provide the security requirements against the untrusted medium. In modern application and the use of modern technologies, the cryptography is used with four specific requirements:

· Authentication: The process of proving one's identity. (The primary forms of host-to-host authentication on the Internet today are name-based or address-based, both of which are notoriously weak.)

· Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.

· Integrity: Assuring the receiver that the received message has not been altered in any way from the original.

· Non-repudiation: A mechanism to prove that the sender really sent this message.

Conclusion

Cryptography, as based from the early messages are not entirely made to protect the data or information from the unwanted persons but is also used to see if the receiver and /or user is authentic. This type of scheme is used to prevent any alteration of information and maintain the privacy of the messages.

References:

Jia, X., Qiang, X.M., Weiqi, Z., & Qian, Z., (2004) Classical Cryptography [Online] Available at: http://www.comp.nus.edu.sg/~xujia/Classical%20Cryptography.pdf [Accessed 16 August 2010]

Kessler, G.C., (2010) An Overview of Cryptography (Edited Version of 1999 Edition of Handbook on Local Area Networks) [Online] Available at: http://www.garykessler.net/library/crypto.html [Accessed 16 August 2010]